<!DOCTYPE html>
<html>
<body>
<pre>
 Most files in FFmpeg are under the GNU Lesser General Public License version 2.1 or later (LGPL v2.1+). Read the file COPYING.LGPLv2.1 for details. Some other files have MIT/X11/BSD-style licenses. In combination the LGPL v2.1+ applies to FFmpeg.

Some optional parts of FFmpeg are licensed under the GNU General Public License version 2 or later (GPL v2+). See the file COPYING.GPLv2 for details. None of these parts are used by default, you have to explicitly pass --enable-gpl to configure to activate them. In this case, FFmpeg's license changes to GPL v2+.

Specifically, the GPL parts of FFmpeg are:

optional x86 optimization in the files
libavcodec/x86/flac_dsp_gpl.asm
libavcodec/x86/idct_mmx.c
libavfilter/x86/vf_removegrain.asm
the following building and testing tools
compat/solaris/make_sunver.pl
doc/t2h.pm
doc/texi2pod.pl
libswresample/tests/swresample.c
tests/checkasm/*
tests/tiny_ssim.c
the following filters in libavfilter:
signature_lookup.c
vf_blackframe.c
vf_boxblur.c
vf_colormatrix.c
vf_cover_rect.c
vf_cropdetect.c
vf_delogo.c
vf_eq.c
vf_find_rect.c
vf_fspp.c
vf_histeq.c
vf_hqdn3d.c
vf_kerndeint.c
vf_lensfun.c (GPL version 3 or later)
vf_mcdeint.c
vf_mpdecimate.c
vf_nnedi.c
vf_owdenoise.c
vf_perspective.c
vf_phase.c
vf_pp7.c
vf_pullup.c
vf_repeatfields.c
vf_sab.c
vf_signature.c
vf_smartblur.c
vf_spp.c
vf_stereo3d.c
vf_super2xsai.c
vf_tinterlace.c
vf_uspp.c
vf_vaguedenoiser.c
vsrc_mptestsrc.c
Should you, for whatever reason, prefer to use version 3 of the (L)GPL, then the configure parameter --enable-version3 will activate this licensing option for you. Read the file COPYING.LGPLv3 or, if you have enabled GPL parts, COPYING.GPLv3 to learn the exact legal terms that apply in this case.

There are a handful of files under other licensing terms, namely:

The files libavcodec/jfdctfst.c, libavcodec/jfdctint_template.c and libavcodec/jrevdct.c are taken from libjpeg, see the top of the files for licensing details. Specifically note that you must credit the IJG in the documentation accompanying your program if you only distribute executables. You must also indicate any changes including additions and deletions to those three files in the documentation.
tests/reference.pnm is under the expat license.
External libraries
FFmpeg can be combined with a number of external libraries, which sometimes affect the licensing of binaries resulting from the combination.

Compatible libraries
The following libraries are under GPL version 2:

avisynth
frei0r
libcdio
libdavs2
librubberband
libvidstab
libx264
libx265
libxavs
libxavs2
libxvid
When combining them with FFmpeg, FFmpeg needs to be licensed as GPL as well by passing --enable-gpl to configure.

The following libraries are under LGPL version 3:

gmp
libaribb24
liblensfun
When combining them with FFmpeg, use the configure option --enable-version3 to upgrade FFmpeg to the LGPL v3.

The VMAF, mbedTLS, RK MPI, OpenCORE and VisualOn libraries are under the Apache License 2.0. That license is incompatible with the LGPL v2.1 and the GPL v2, but not with version 3 of those licenses. So to combine these libraries with FFmpeg, the license version needs to be upgraded by passing --enable-version3 to configure.

The smbclient library is under the GPL v3, to combine it with FFmpeg, the options --enable-gpl and --enable-version3 have to be passed to configure to upgrade FFmpeg to the GPL v3.

Incompatible libraries
There are certain libraries you can combine with FFmpeg whose licenses are not compatible with the GPL and/or the LGPL. If you wish to enable these libraries, even in circumstances that their license may be incompatible, pass --enable-nonfree to configure. This will cause the resulting binary to be unredistributable.

The Fraunhofer FDK AAC and OpenSSL libraries are under licenses which are incompatible with the GPLv2 and v3. To the best of our knowledge, they are compatible with the LGPL.
    </pre>
</body>
</html>
